Method for fabricating a semiconductor package with a semiconductor device attached to a multilayered substrate

ABSTRACT

A semiconductor device has (a) a semiconductor component; (b) a circuit substrate; (c) a base material which is placed between the semiconductor component and the circuit substrate; and (d) a conductive paste, which is filled into a hole formed in the base material, for electrically connecting between a terminal electrode of the semiconductor component and an internal connection electrode of the circuit substrate.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a semiconductor device which ispackaged for the mounting of a semiconductor component onto a circuitsubstrate, and to a method of manufacturing the same.

2. Description of the Related Art

There have been developed many types of packaging technologiesincluding, as a typical one, quad flat pack (QFP). These packagingtechniques are used to provide, at the time of mounting a semiconductorcomponent onto a circuit substrate, facilitation of the protection andthe mounting of semiconductor components. Because of the increase inconnection terminal count in semiconductor components, the package sizeof semiconductor components is on the increase. Accordingly, it isbecoming difficult for such conventional packaging technologies to dealeffectively with demands for the reduction of mounting area.

With a view to meeting the demands, there has been devised a techniquein which a bare semiconductor component is directly mounted onto acircuit substrate for the reduction and effective use of mounting area.For example, when a semiconductor component is connected to a circuitsubstrate, a layer of vapor-deposited adhesive metal or a layer ofvapor-deposited diffusion protection metal is preformed on a terminalelectrode of the semiconductor component and a projecting electrode ofsolder formed by plating is constructed overlying the layer.Subsequently, the semiconductor component is faced down and heated up toa high temperature. As a result of such application of heat, the solderis fused to a connection electrode of the circuit substrate. Such amounting method is considered an effective technique because it canprovide high post-connection mechanical strength and establishconnection in a single process (“IC MOUNTING TECHNOLOGY”, edited byJapan Microelectronics Association, published on Jan. 15, 1980,Institute for Industrial Research).

In addition to the above-described method, there have been proposedother methods. For instance, U.S. Pat. No. 5,121,190 and Japanese PatentApplication (unexamined) Pub. No. 6-61303 show mounting techniques andsemiconductor devices in which a molding compound is used to secure thestability of solder joints. One such conventional semiconductor devicewill be described below by reference to FIGS. 7 and 8. FIG. 7 shows alayout of terminal electrodes of a commonly-used semiconductorcomponent. FIG. 8 shows in cross section major parts of a conventionalsemiconductor device with a semiconductor component mounted face down.

In the terminal electrode layout of FIG. 7, terminal electrodes 16 arelaid out around the periphery of a semiconductor component 15. In orderto deal with an increase in the number of terminal electrodes 16, it isrequired to either reduce the gap between terminal electrodes 16 orincrease the size of the semiconductor component 15 for coping with suchan electrode number increase.

The semiconductor device of FIG. 8, in which the semiconductor component15 is mounted face down, comprises, in addition to the semiconductorcomponent 15, a terminal electrode 16 of the semiconductor component 15,a circuit substrate 17, a connection electrode 18 formed on a surface ofthe circuit substrate 17, a solder joint 19 which joints together theconnection electrode 18 and the terminal electrode 16, a molding(sealing) resin 20 which seals the semiconductor component 15, and otherstructural elements.

A method of manufacturing a conventional semiconductor device having theabove-described structure will be described below. In the first place, aprojecting electrode of solder is preformed on the terminal electrode 16of the semiconductor component 15. Thereafter, the semiconductorcomponent 15 is mounted, in face down fashion, onto the circuitsubstrate 17. This is followed by alignment of the solder projectingelectrode with a given position of the connection electrode 18. Next,the solder is melted by application of high-temperature heat (from 200to 300 degrees centigrade), and the solder projecting electrode and theconnection electrode 18 are joined together. In this way, thesemiconductor component 15 is fixed to the circuit substrate 17 by thesolder joint 19. Thereafter, a gap, created between the semiconductorcomponent 15 and the circuit substrate 17, is filled with the moldingresin 20 in the form of liquid. By heat hardening at about 120 degreescentigrade, the molding resin 20 is solidified. In this way, themounting of the semiconductor component 15 onto the circuit substrate 17is completed to provide a semiconductor device as shown in FIG. 8.

However, the above-described conventional semiconductor devices andassociated manufacture methods have the following drawbacks.

Firstly, in order to protect the surface of the semiconductor component15, it is required to fill a gap between the semiconductor component 15and the circuit substrate 17 with the molding resin 20, and the mountingsize increases accordingly. Therefore, when used as a packagedsemiconductor device, its size becomes greater than that of thesemiconductor component 15.

Secondly, if the number of terminal electrodes 16 of the semiconductorcomponent 15 increases as the circuit scale increases, then the gapbetween adjacent terminal electrodes 16 is made narrower, resulting inreducing the size and the pitch of the solder joint 19 and consequentlythe reliability of the solder joint 19 between the semiconductorcomponent 15 and the circuit substrate 17 will drop.

Thirdly, in order to facilitate the mounting of the terminal electrodes16 laid out around the periphery of the semiconductor component 15 inface-down manner, it is required to use a multi-level wiring techniquemaking use of a thin film technology for two-dimensionally placing theterminal electrodes 16 on the semiconductor component 15, to increasethe size and the pitch of the terminal electrodes 16. However, sucharrangement produces some problems, that is, semiconductor device yieldis decreased and manufacturing costs are increased.

In view of the above, there is the limit of down-sizing semiconductordevices, improving their reliability to a further extent, and reducingtheir production costs and therefore the foregoing prior art techniquesare not very practical. Particularly, in order to deal with the increasein the number of terminals in a semiconductor component, theabove-described problems become increasingly serious.

SUMMARY OF THE INVENTION

The present invention was made with a view to providing solutions to theforegoing problems with the prior art techniques. Accordingly, an objectof the present invention is to provide a down-sized, thinned,highly-reliable semiconductor device capable of dealing with higherterminal count, and a method of manufacturing the same.

One aspect of the present invention is a semiconductor devicecomprising:

(a) a semiconductor component;

(b) a circuit substrate;

(c) a base material which is placed between said semiconductor componentand said circuit substrate; and

(d) a conductive paste, which is filled into a hole formed in said basematerial, for electrically connecting between a terminal electrode ofsaid semiconductor component and an internal connection electrode ofsaid circuit substrate.

Another aspect of the present invention is a semiconductor devicecomprising:

(a) a semiconductor component;

(b) a circuit substrate; and

(c) a conductive paste, which is filled into a hole formed in a surfaceof said circuit substrate at the side of said semiconductor component,for electrically connecting between a terminal electrode of saidsemiconductor component and an external connection electrode of saidcircuit substrate.

Still another aspect of the present invention is a method ofmanufacturing a semiconductor device in which a semiconductor componentis mounted onto a circuit substrate, said semiconductor devicemanufacture method comprising:

(a) a hole forming step of forming a hole in a base material;

(b) a paste filling step of filling a conductive paste into said hole;and

(c) a connecting step of mechanically connecting said semiconductorcomponent to said circuit substrate through said base material while atthe same time electrically connecting between a terminal electrode ofsaid semiconductor component and a connection electrode of said circuitsubstrate by said conductive paste.

Such arrangement eliminates the need for filling a gap between thesemiconductor component and the circuit board (or the base material)with a molding resin, whereby the mounting size of semiconductorcomponents can be reduced down to the size of semiconductor components.

Additionally, by the use of a multi-layered substrate for converting alayout of terminal electrodes placed around the periphery of asemiconductor component into a two-dimensional layout, it becomespossible to provide a semiconductor device capable of easily dealingwith an increase in the number of terminal electrodes in a semiconductorcomponent.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates in cross section successive steps of a method ofmanufacturing a semiconductor device according to a first embodiment ofthe present invention.

FIG. 2 illustrates in cross section a structure of the semiconductordevice of the first embodiment.

FIG. 3 is an illustration of a layout of external connection terminalsof the semiconductor device of the first embodiment.

FIG. 4 illustrates in cross section a structure of a semiconductordevice according to a second embodiment of the present invention.

FIG. 5 illustrates in cross section a structure of a semiconductordevice according to a third embodiment of the present invention.

FIG. 6 illustrates in cross section a structure of a semiconductordevice according to a fourth embodiment of the present invention.

FIG. 7 is an illustration of a layout of terminal electrodes of acommonly-used semiconductor component.

FIG. 8 illustrates in cross section major parts of a conventionalsemiconductor device in which a semiconductor component is mounted inface down manner.

REFERENCE NUMERALS IN DRAWINGS

1 ORGANIC FILM

2 ADHESIVE LAYER

3 RELEASABLE FILM

4 PENETRATION HOLE

5 CONDUCTIVE PASTE

6 SEMICONDUCTOR COMPONENT

7 TERMINAL ELECTRODE

8 MULTI-LAYERED SUBSTRATE

9 CONNECTION ELECTRODE

10 COMPRESSED CONDUCTIVE PASTE

11 EXTERNAL CONNECTION TERMINAL

12 POROUS BASE MATERIAL

13 PROJECTING ELECTRODE

14 MULTI-LAYERED SUBSTRATE WITH A SURFACE LAYER OF DUCTIVE PASTE

15 SEMICONDUCTOR COMPONENT

16 TERMINAL ELECTRODE

17 CIRCUIT SUBSTRATE

18 CONNECTION ELECTRODE

19 SOLDER JOINT

20 MOLDING RESIN

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the present invention will be described below by makingreference to the attached drawings.

(First Embodiment)

Referring to the drawings, a first embodiment of the present inventionis now described below.

FIG. 1 illustrates in cross section successive steps of a method ofmanufacturing a semiconductor device in the first embodiment of thepresent invention. FIG. 2 is a cross sectional view of a structure ofthe semiconductor device of the first embodiment. FIG. 3 is anillustration of a layout of external connection terminals of thesemiconductor device of the first embodiment. It is to be noted that thedimensions of structural elements depicted in these figures areexaggerated for the sake of convenience of the description of thepresent invention.

As shown in FIGS. 2 and 3, the semiconductor device of the presentembodiment comprises the following: a semiconductor component 6, aterminal electrode 7 formed on the semiconductor component 6, amulti-layered substrate 8, an external connection terminal 11 which istwo-dimensionally laid out on one of the surfaces of the multi-layeredsubstrate 8 opposite to the other surface thereof to which thesemiconductor component 6 is connected, an organic film 1 which has, oneach of its surfaces, an adhesive layer 2 for mechanically connectingbetween the semiconductor component 6 and the multi-layered substrate 8,a conductive paste 5 for electrically connecting between thesemiconductor component 6 and the multi-layered substrate 8, and othercomponents. In FIGS. 1(a) to 1(e), reference numeral 3 represents areleasable film. Reference numeral 4 represents a penetration hole.Reference numeral 9 represents a connection terminal. Reference numeral10 represents the conductive paste compressed. FIG. 3 shows that thenumber of external connection terminals 11 formed on the multi-layeredsubstrate's 8 surface is 10 by 10 (=100). However, in FIGS. 1 and 2,only sixteen (4 by 4) external connection terminals 11 are shown incross section for the sake of convenience.

Meanwhile the whole can be non-passed type.

Next, a method of manufacturing a semiconductor device in accordancewith the present embodiment will be described below.

In the first place, the adhesive layer 2 (for example, an epoxy resinlayer) is formed on both surfaces of the organic film 1 which is anon-compressible base material (e.g., an aramide film), and a basematerial is prepared carrying on both surfaces thereof the releasablefilm 3 (FIG. 1(a)).

Next, the penetration hole 4 is formed at a given position of theorganic film 1 by laser-beam machining or the like technique (FIG.1(b)). This step corresponds to the step of forming a penetration holein the present invention.

Subsequently, the penetration hole 4 is filled with the conductive paste5 (FIG. 1(c)). The step of filling the penetration hole 4 with theconductive paste 5 is carried out as follows. The organic film 1 withthe penetration hole 4 is placed on the table of a printer and theconductive paste 5 is printed directly from over the releasable film 3.At this time, the overlying releasable film 3 acts as a printing maskwhile protecting the surface of the adhesive layer 2 from beingcontaminated. This step corresponds to the step of filling a paste inthe present invention.

Thereafter, the releasable films 3 are peeled off from the surfaces ofthe adhesive layer 2. One of the surfaces of the adhesive layer 2 isaligned with the terminal electrode 7 of the semiconductor component 6and the other of the surfaces of the adhesive layer 2 is aligned withthe connection electrode 9 of the multi-layered substrate 8 forlamination (FIG. 1(d)) This is followed by application of heat/pressure,so that the semiconductor component 6 and the multi-layered substrate 8are mechanically connected together by the adhesive layer 2 (FIG. 1(e)).Further, in this step, the conductive paste 5 is compressed, as a resultof which a conductive substance of the conductive paste 5 is densifiedat the same time that the conductive substance hardens. The terminalelectrode 7 of the semiconductor component 6 and the connectionelectrode 9 of the multi-layered substrate 8 are electrically connectedtogether by the compressed conductive paste 10. A combination of thestep of FIG. 1(d) and the step of FIG. 1(e) corresponds to theconnecting step of the present invention.

The base material of film 1 may include self-adhesive properties. Inconnecting semiconductor component 6 to substrate 8 utilization may bemade of the self-adhesiveness of the base material of film 1.

(Second Embodiment)

A second embodiment of the present invention will be described byreference to the drawings. The present embodiment relates to asemiconductor device that is identical with the one disclosed in thefirst embodiment, with the exception that the present embodiment employsa base material layer which is composed mainly of a compressible basematerial. Accordingly, the same reference numerals have been used toindicate basically like elements in the present embodiment and the firstembodiment and their description is omitted. Especially, as to theelements that are not described here, they are to be regarded as thesame ones as described in the first embodiment.

FIG. 4 depicts in cross section a structure of the semiconductor devicein accordance with the second embodiment. When compared with the firstembodiment, the present embodiment has substantially the same structureas the first embodiment, with the exception that in the secondembodiment, a porous base material 12 is used in place of the organicfilm 1.

The semiconductor device of the present embodiment is manufactured usingsubstantially the same fabrication steps as in the first embodiment.

The porous base material 12 (e.g., a composite material prepared byimpregnating aromatic polyamide fiber with a thermosetting epoxy resin)is used as a base material for establishing mechanical and electricalconnection between the semiconductor component 6 and the multi-layeredsubstrate 8. The use of the porous base material 12 provides, inaddition to the effects of the first embodiment, the advantage thatsince the porous base material 12 is easily compressed duringapplication of heat and pressure in the connecting step of the presentinvention, the conductive substance of the conductive paste 5 isdensified to a further extent.

(Third Embodiment)

A third embodiment of the present invention will be explained byreference to the drawings. The present embodiment relates to asemiconductor device which is identical with the one disclosed in thefirst embodiment, with the exception that in the present embodiment, thesemiconductor component of the semiconductor device includes aprojecting electrode. Accordingly, the same reference numerals have beenused to indicate basically like elements in the present embodiment andthe first embodiment and their description is omitted. Especially, as tothe elements that are not described here, they are to be considered asthe same ones as described in the first embodiment.

Referring to FIG. 5, there is shown in cross section a structure of thesemiconductor device according to the third embodiment. When comparedwith the first embodiment, the present embodiment has substantially thesame structure as the first embodiment, with the exception that in thepresent embodiment, a projecting electrode 13 is formed, overlying theterminal electrode 7 of the semiconductor component 6.

A method of manufacturing a semiconductor device of the presentembodiment will be described. This method employs substantially the samesteps as in the first embodiment, with the exception that the presentembodiment includes, prior to the connecting step of the semiconductormanufacture method of the first embodiment, a step of forming theprojecting electrode 13 on the terminal electrode 7 of the semiconductorcomponent 6, and that in the connecting step of the present embodiment,the terminal electrode 7 and the connection electrode 9 are electricallyconnected together by a conductive paste through the projectingelectrode 13.

The formation of the projecting electrode 13 on the terminal electrode 7of the semiconductor component 6 provides, in addition to the effects ofthe first embodiment, the advantage that since the conductive paste 5 iscompressed by an amount corresponding to the projecting electrode 13during application of heat and pressure in a step of the manufacture ofthe semiconductor device, the conductive substance of the conductivepaste 5 is densified to a further extent.

If a semiconductor component of the semiconductor device of the secondembodiment has a structure including a projecting electrode of thepresent invention, this provides, in addition to the effects of thesecond embodiment, the advantages that the conductive substance of theconductive paste 5 is densified to a further extent, as in the above.

(Fourth Embodiment)

A fourth embodiment of the present invention will be described byreference to the drawings. The present embodiment relates to asemiconductor device which is identical with the one disclosed in thefirst embodiment, with the exception that in the semiconductor device ofthe present embodiment, the circuit substrate has an adhesive layer anda conductive paste of the present invention and that no base material ofthe present invention is used. Accordingly, the same reference numeralshave been used to indicate basically like elements in the presentembodiment and the first embodiment and their description is omitted.Especially, as to the elements that are not described here, they are tobe regarded as the same ones as described in the first embodiment.

Referring to FIG. 6, there is shown in cross section a structure of thesemiconductor device according to the fourth embodiment. When comparedwith the first embodiment, the present embodiment has substantially thesame structure as the first embodiment, with the exception that in thepresent embodiment, a multi-layered substrate 14 is employed. Formed ona surface layer of the multi-layered substrate 14 that is connected tothe semiconductor component 6 is the conductive paste 10 and theadhesive layer 2.

The use of the multi-layered substrate 14 (which carries, on its surfacelayer that is connected to the semiconductor component 6, the conductivepaste 10 and the adhesive layer 2) provides, in addition to the effectsof the first embodiment, the advantage that base materials, such as theorganic film 1 and the porous base material 12, are no longer neededtherefore making it possible to provide a much thinner semiconductordevice.

Meanwhile the hole can be passed through type.

In each of the above-described embodiments of the present invention,resins (e.g., epoxy resin, silicone resin, and phenol resin) containingfine powders of Ag, Au, Cu, Ni, or the like can be used as materials forthe conductive paste 10 as long as these resins have satisfactoryconductivity and are thermosettable.

Even if the circuit substrate of the semiconductor device in the secondor third embodiment is constructed to include an adhesive layer and aconductive paste of the present invention and to have no base materialof the present invention, such arrangement provides, in addition to theeffects of the second or third embodiment, the same advantage asdescribed above.

It has been described in the first to fourth embodiments that thecircuit substrate of the present invention is implemented by amulti-layered substrate that has, on one of the surfaces thereof facingthe semiconductor component as well as on the opposite surface, externalconnection terminals arranged two-dimensionally in a matrix. This is notconsidered to be restrictive. For instance, these external connectionterminals can be arranged two-dimensionally at random.

Additionally, it has been described that the conductive substance of theconductive paste used in the present invention is densified bycompression. This is not considered to be restrictive. Even if suchcompaction by compression is omitted, it is possible to provide aneffect of manufacturing a down-sized, thinned semiconductor device.

As can be seen from the above-description, the present invention is ableto provide a down-sized, thinned, highly-reliable semiconductor devicecapable of dealing with the increase in terminal count, and a method ofmanufacturing the same.

In other words, by the use of a multi-layered substrate capable of atwo-dimensional conversion of the layout of the terminal electrodesplaced around the periphery of a semiconductor component in the presentinvention, it becomes possible to provide a semiconductor device that isable to easily deal with an increase in the number of terminalelectrodes in a semiconductor component.

In accordance with the semiconductor device manufacture method of thepresent invention, there is no need to fill a gap, created between thesemiconductor component and the circuit substrate (or the base material)with a molding resin, and it becomes possible to reduce the mountingsize of semiconductor component to the size of semiconductor component.

What is claimed is:
 1. A method of manufacturing a semiconductor devicein which a semiconductor component is mounted onto a circuit substrate,said semiconductor device manufacture method comprising the steps of:(a) forming a hole in a base material; (b) filling a conductive pasteinto said hole; (c) pressing said semiconductor component onto saidcircuit substrate through said base material for compressing the basematerial while at the same time electrically connecting a terminalelectrode of said semiconductor component and a connection electrode ofsaid circuit substrate by said conductive paste; and (d) cutting saidbase material and said circuit substrate into the same size afterpressing said semiconductor component to said circuit substrate.
 2. Thesemiconductor device manufacture method according to claim 1, whereinsaid hole and a surface of said base material at a side of said circuitsubstrate are connected together by an IVH (inner via hole) structure.3. The semiconductor device manufacture method according to claim 2,wherein at least the surface of said base material at a side of saidsemiconductor component is self-adhesive, and in said hole forming step,said hole is formed in at least said base material surface at the sideof said semiconductor component.
 4. The semiconductor device manufacturemethod according to claim 3, wherein in said pressing step isestablished by making utilization of the self-adhesiveness of said basematerial.
 5. The semiconductor device manufacture method according toclaim 2, wherein said base material has, on at least the surface of saidbase material at a side of said semiconductor component, an adhesivelayer, and in said hole forming step, said hole is formed such that saidhole passes through at least said adhesive layer.
 6. The semiconductordevice manufacture method according to claim 5, wherein said pressingstep is established by making utilization of said adhesive layer of saidbase material.
 7. The semiconductor device manufacture method accordingto claim 1, wherein said base material has, on at least a surface ofsaid base material at a side of said semiconductor component, anadhesive layer, and in said hole forming step, said hole is formed suchthat said hole passes through at least said adhesive layer.
 8. Thesemiconductor device manufacture method according to claim 7, whereinsaid pressing step is established by making utilization of said adhesivelayer of said base material.
 9. The semiconductor device manufacturemethod according to claim 1, wherein at least a surface of said basematerial at a side of said semiconductor component is self-adhesive, andin said hole forming step, said hole is formed in at least said basematerial surface at the side of said semiconductor component.
 10. Thesemiconductor device manufacture method according to claim 9, whereinsaid pressing step is established by making utilization of theself-adhesiveness of said base material.
 11. The semiconductor devicemanufacture method according to claim 1, wherein said semiconductorcomponent has a projecting electrode on said terminal electrode, and insaid connecting step, said terminal electrode is electrically connectedto said connection electrode through said projecting electrode and saidconductive paste.
 12. The semiconductor device manufacture methodaccording to claim 1, wherein in said pressing step, a conductivesubstance contained in said conductive paste is densified bycompression.
 13. A method of manufacturing a semiconductor deviceaccording to claim 1, wherein in said cutting step (d), said basematerial and said circuit substrate are cut into the size of saidsemiconductor component.
 14. A method of manufacturing a semiconductordevice according to claim 1, wherein said base material is an organicfilm.
 15. A method of mounting a terminal electrode of a semiconductorcomponent onto a circuit substrate, the semiconductor component having aplurality of terminal electrodes arranged along a peripheral boundary ofthe semiconductor component, comprising the steps of: (a) forming anadhesive layer on each of opposite surfaces of a base material; (b)forming a releasable film on each adhesive layer formed in step (a); (c)forming a hole in the base material; (d) filling the hole with aconductive paste; (e) peeling away the releasable film on each of theadhesive layers after filling the hole in step (d); (f) forming thecircuit substrate including the following steps: (f1) providing a firstplurality of external terminals on one surface of the circuit substrate,the first plurality of external terminals arranged to mate with theplurality of terminal electrodes of the semiconductor component; (f2)providing a second plurality of external terminals on another surface ofthe circuit substrate, the second plurality of external terminalsarranged in a matrix array format; and (f3) connecting electrically,inside the circuit substrate, the first plurality of external terminalsto the second plurality of external terminals; (g) sandwiching the basematerial between the semiconductor component and the circuit substrateand pressing the semiconductor component onto the circuit substrate tocompress the base material and the conductive paste; and (h) mating aterminal electrode of the semiconductor component with one externalterminal of the first plurality of external terminals, whereby theterminal electrode of the semiconductor component is electricallyconnected to an external terminal of the second plurality of externalterminals.
 16. A method of manufacturing a semiconductor device having aplurality of terminal electrodes in which a semiconductor component ismounted onto a circuit substrate having a plurality of connectionelectrodes, said semiconductor device manufacture method comprising thesteps of: (a) forming an adhesive layer on each of opposite surfaces ofa base material; (b) forming a releasable film on each adhesive layerformed in step (a); (c) forming a hole in the base material; (d) fillinga conductive paste into the hole; (e) peeling away the releasable filmon each of the adhesive layers after filling the hole in step (d); and(f) pressing the semiconductor component onto the circuit substrate, forcompressing the base material and the conductive paste, and electricallyconnecting a terminal electrode of said semiconductor component, aconnection electrode of said circuit substrate, and the conductivepaste.